1. Field of the Invention
This invention relates generally to ground proximity warning systems, and more particularly to a system that protects an aircraft during low altitude maneuvers if the aircraft should descend below a predetermined minimum altitude above ground, or if the aircraft exceeds a predetermined descent rate while performing turning maneuvers or other maneuvers requiring a roll. Distinct specific warnings are given in order to inform the pilot of the specific action that must be taken to recover from a dangerous flight profile.
2. Description of the Prior Art
Ground proximity warning systems that warn a pilot of a dangerous flight profile are known. These systems provide warnings to the pilot of an aircraft under various unsafe flying conditions including flying below a preset minimum altitude, and permitting the aircraft to attain an excessive descent rate after take-off or on approach. An example of a system that provides a pilot with a warning if he drops below a predetermined minimum desired altitude is a system that compares the radio altitude with the minimum decision altitude setting, or "bug" setting on the radio altimeter, and provides an aural or visual warning if the radio altitude drops below the set minimum decision altitude. Examples of systems that provide a warning to a pilot during a take-off or a missed approach phase of operation if the aircraft should descend at an excessive barometric rate or lose a predetermined amount of barometric altitude are disclosed in U.S. Pat. Nos. 3,946,358; 3,947,808; 3,947,810 and 4,319,218, assigned to the same assignee as the present invention.
While these systems serve to provide the pilot with a warning in the event that the aircraft drops below a preset minimum desired altitude above ground, or if the aircraft descends excessively after take-off or a missed approach, such systems are designed primarily for transport aircraft that do not normally fly at low altitudes or execute turns or other severe or violent maneuvers near the ground. Consequently, such systems would not normally provide adequate warning to the pilot of a highly maneuverable aircraft such as, for example, a fighter/attack aircraft executing tactical maneuvers near the ground.